4 SEEDING AND PLANTING 



about by less expensive methods. Successful reproduction de- 

 mands a full stand, because without it the land will not be fully 

 utilized and the product, if not less in quantity, will be of inferior 

 quality. 



3. Chief Aim in Improvement 



The operations which affect the improvement of the forest are 

 chiefly concerned with thinning, pruning, and the protection of 

 the crop. The aim is to attain a full stand of the most valuable 

 species or crop trees of the best form and most rapid growth 

 consistent with fullness of stand and quality of product. 



Nearly always in natural regeneration, and even in seeding and 

 planting in mixtures, the resulting reproduction is not wholly of 

 the desired composition. It very often arises that during the 

 progress of the growth of the stand the species of greatest market 

 value are crowded out. Well-directed thinnings made at the proper 

 time hold the inferior species in check and enable the superior ones 

 to thrive and ultimately to become the crop trees. Thinnings 

 also enable the forester to favor the trees which have the best 

 form and those which will produce wood of the highest quality. 

 Those with crooked boles or otherwise undesirable are removed 

 in the thinnings. By starting with a full reproduction, the thin- 

 nings can be made to induce the most rapid growth in the crop 

 trees and, at the same time, develop a product of high quality. 

 The pruning of the crop trees aids chiefly in improving the quality 

 of the product. The protection of the forest from external 

 harmful agencies such as fire, insects, and fungous diseases, is an 

 important part of forest improvement since they may seriously 

 affect not only the composition of the stand but the rate of growth 

 and the quality of the product. 



4. NATURAL REPRODUCTION IN THE VIRGIN FOREST 



In the virgin forest, as the trees mature, die and fall to the 

 ground, their places are taken by younger trees. Reproduction 

 takes place in more or less isolated patches where openings occur 

 (Fig. 3). As a result, the typical virgin forest in its climax 

 form contains trees of all ages. It is fully stocked at all times, 

 unless disturbed by fire, insects, or other external agents which 

 cause the destruction of all, or a large number, of the trees 

 at one time. In such a forest natural reproduction is easily at- 



